Numerous electronic circuits require protection from damage due to electrostatic discharge (ESD) caused by rapid discharge of static electricity from one conductor to another having a different potential. ESD can damage integrated circuits in computers, communication equipment, and countless other types of electronic equipment. Semiconductor circuits and components built to provide ESD protection are conventionally implemented using components such as silicon controlled rectifiers (SCRs), Shockley diodes, thyristors, latches, and metal gate field oxide (MGFO) devices. These conventional devices provide ESD protection between two terminals for either positive or negative ESD voltage swings. For example, an SCR usually snaps back in either a positive or a negative voltage direction and operates as a simple diode in the other direction. In addition, these devices are typically built to handle only a specific voltage or narrow voltage range, which is dictated by the doping levels of the diffusions that break down.
The ESD protection devices conventionally available generally suffer from lack of control of all critical device parameters, due to physical design parameters. These conventional devices are designed to provide ESD protection either in a positive voltage direction or a negative voltage direction. However, with the advent of complex electronic circuits and smart power integrated circuits (ICs), design requirements now include a greater range of values of breakdown voltages. Devices that can span a wide voltage range are finding an increasing need in applications including automotive and residential electronics. Since conventional ESD protection fails to handle a wide range of voltages and currents in both the positive and negative direction, a breakdown voltage requirement for a particular device can result in having to design a new device.
Therefore, there is a need to provide an ESD protection device to protect against a wide range of positive and negative voltages. Such a device structure should be flexible enough to provide varying ESD properties without significant re-design of device structure or addition/deletion of a significant number of doping regions.